AFib and Strokes: You Could Be At Risk and Not Know It

A racing, pounding heartbeat that can hit for no apparent reason should never be ignored. And it can be especially serious when the accelerated or irregular heartbeat presents with shortness of breath after light physical activity or lightheadedness, dizziness, or unusual fatigue.

Studies have shown that too many people affected by this condition, known as atrial fibrillation (AFib), do not realize they have it and may delay getting help. AFib is an irregular heartbeat during which the heart muscles fail to contract in a strong and rhythmic way. When a heart is in AFib, it may not be pumping enough oxygen-rich blood out to the body.

The most serious risk factor for those with a AFib is a stroke. AFib is associated with a five-times-greater risk for stroke. That’s because the abnormal rhythm can lead to blood pooling in the heart’s atria and form clots, blocking the arteries and depriving the brain of oxygen.

There are two atria in the upper chamber of the human heart that receive blood. The left atrium gets blood from the lungs, and the right atrium from the venous circulation around the body. The heart muscle contracts to pump blood to the ventricles, which make up the lower two chambers of the heart.

“Anytime someone is diagnosed with atrial fibrillation, our biggest concern is the risk of stroke,” says Mario Pascual, M.D., an electrophysiologist with Miami Cardiac & Vascular Institute. When the heart is in AFib, the blood can become “static and can be left pooling inside the heart,” says Dr. Pascual. That creates an ideal setting for a blood clot to form.

“When blood pools, a clot can form,” he adds. “When a clot is pumped out of the heart, it can get lodged in the arteries, which may cause a stroke. Blocked arteries prevent the tissue on the other side from getting oxygen-rich blood, and without oxygen, the tissue dies.”

Diagnosing AFib
AFib can increase your risk for heart failure and other heart-related complications. But any person who has AFib needs to evaluate the risk for stroke and discuss ways of lower that risk with a primary care physician or cardiologist. Studies show that many people with AFib who need treatment to lower stroke risks are not getting getting help.

Additionally, AFib can be challenging to diagnose. An estimated 60 percent of AFib patients will have symptoms, says Dr. Pascual. The most common diagnostic tool is an electrocardiogram — also called ECG or EKG — which is a test often done in a doctor’s office, a clinic or a hospital room. But AFib can come and go, so it’s not always that simple, says Dr. Pascual.

Symptoms of AFib include:
• Palpitations, which are sensations of a racing, unusual or irregular heartbeat or a fluttering in the chest
• Shortness of breath
• Not doing everyday activities that someone normally does
• Not being able to exercise as well as they use to
• Fatigue
• Lightheadedness
• Dizziness

AFib-Related Strokes
If you’re having AFiib-like symptoms, start out with your primary care doctor and describe some of the irregular-heartbeat episodes you’re having. Your primary will likely refer you to a cardiologist or an electrophysiologist to truly discover what’s driving your symptoms. Treatments for atrial fibrillation may include medications and other interventions to attempt to normalize the heart’s electrical system.

It’s important to keep in mind that AFib-related strokes can be serious. They are referred to as “large volume” strokes, says Dr. Pascual.

“These strokes are associated with large blood clots that can happen in the upper chambers of the heart,” says Dr. Pascual. “Of course, the larger the blood clot that can shoot off to the brain, the more severe the stroke. As opposed to small strokes that can be caused by plaque rupture, these strokes from atrial fibrillation can produce large blood clots that can move to the brain.”